2 * Copyright (C) 1999,2000 Erik Walthinsen <omega@cse.ogi.edu>
3 * 2004 Wim Taymans <wim@fluendo.com>
5 * gstelement.c: The base element, all elements derive from this
7 * This library is free software; you can redistribute it and/or
8 * modify it under the terms of the GNU Library General Public
9 * License as published by the Free Software Foundation; either
10 * version 2 of the License, or (at your option) any later version.
12 * This library is distributed in the hope that it will be useful,
13 * but WITHOUT ANY WARRANTY; without even the implied warranty of
14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
15 * Library General Public License for more details.
17 * You should have received a copy of the GNU Library General Public
18 * License along with this library; if not, write to the
19 * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
20 * Boston, MA 02111-1307, USA.
25 * @short_description: Abstract base class for all pipeline elements
26 * @see_also: #GstElementFactory, #GstPad
28 * GstElement is the abstract base class needed to construct an element that
29 * can be used in a GStreamer pipeline. Please refer to the plugin writers
30 * guide for more information on creating #GstElement subclasses.
32 * The name of a #GstElement can be get with gst_element_get_name() and set with
33 * gst_element_set_name(). For speed, GST_ELEMENT_NAME() can be used in the
34 * core when using the appropriate locking. Do not use this in plug-ins or
35 * applications in order to retain ABI compatibility.
37 * All elements have pads (of the type #GstPad). These pads link to pads on
38 * other elements. #GstBuffer flow between these linked pads.
39 * A #GstElement has a #GList of #GstPad structures for all their input (or sink)
40 * and output (or source) pads.
41 * Core and plug-in writers can add and remove pads with gst_element_add_pad()
42 * and gst_element_remove_pad().
44 * A pad of an element can be retrieved by name with gst_element_get_pad().
45 * An iterator of all pads can be retrieved with gst_element_iterate_pads().
47 * Elements can be linked through their pads.
48 * If the link is straightforward, use the gst_element_link()
49 * convenience function to link two elements, or gst_element_link_many()
50 * for more elements in a row.
51 * Use gst_element_link_filtered() to link two elements constrained by
52 * a specified set of #GstCaps.
53 * For finer control, use gst_element_link_pads() and
54 * gst_element_link_pads_filtered() to specify the pads to link on
55 * each element by name.
57 * Each element has a state (see #GstState). You can get and set the state
58 * of an element with gst_element_get_state() and gst_element_set_state().
59 * To get a string representation of a #GstState, use
60 * gst_element_state_get_name().
62 * You can get and set a #GstClock on an element using gst_element_get_clock()
63 * and gst_element_set_clock().
64 * Some elements can provide a clock for the pipeline if
65 * gst_element_provides_clock() returns %TRUE. With the
66 * gst_element_provide_clock() method one can retrieve the clock provided by
68 * Not all elements require a clock to operate correctly. If
69 * gst_element_requires_clock() returns %TRUE, a clock should be set on the
70 * element with gst_element_set_clock().
72 * Note that clock slection and distribution is normally handled by the
73 * toplevel #GstPipeline so the clock functions are only to be used in very
74 * specific situations.
76 * Last reviewed on 2009-05-29 (0.10.24)
79 #include "gst_private.h"
82 #include <gobject/gvaluecollector.h>
84 #include "gstelement.h"
85 #include "gstenumtypes.h"
87 #include "gstmarshal.h"
93 #include "gst-i18n-lib.h"
95 /* Element signals and args */
111 extern void __gst_element_details_clear (GstElementDetails * dp);
112 extern void __gst_element_details_copy (GstElementDetails * dest,
113 const GstElementDetails * src);
115 static void gst_element_class_init (GstElementClass * klass);
116 static void gst_element_init (GstElement * element);
117 static void gst_element_base_class_init (gpointer g_class);
118 static void gst_element_base_class_finalize (gpointer g_class);
120 static void gst_element_dispose (GObject * object);
121 static void gst_element_finalize (GObject * object);
123 static GstStateChangeReturn gst_element_change_state_func (GstElement * element,
124 GstStateChange transition);
125 static GstStateChangeReturn gst_element_get_state_func (GstElement * element,
126 GstState * state, GstState * pending, GstClockTime timeout);
127 static GstStateChangeReturn gst_element_set_state_func (GstElement * element,
129 static void gst_element_set_bus_func (GstElement * element, GstBus * bus);
131 static gboolean gst_element_default_send_event (GstElement * element,
133 static gboolean gst_element_default_query (GstElement * element,
136 static GstPadTemplate
137 * gst_element_class_get_request_pad_template (GstElementClass *
138 element_class, const gchar * name);
140 #ifndef GST_DISABLE_LOADSAVE
141 static xmlNodePtr gst_element_save_thyself (GstObject * object,
143 static void gst_element_restore_thyself (GstObject * parent, xmlNodePtr self);
146 static GstObjectClass *parent_class = NULL;
147 static guint gst_element_signals[LAST_SIGNAL] = { 0 };
149 /* this is used in gstelementfactory.c:gst_element_register() */
150 GQuark _gst_elementclass_factory = 0;
153 gst_element_get_type (void)
155 static volatile gsize gst_element_type = 0;
157 if (g_once_init_enter (&gst_element_type)) {
159 static const GTypeInfo element_info = {
160 sizeof (GstElementClass),
161 gst_element_base_class_init,
162 gst_element_base_class_finalize,
163 (GClassInitFunc) gst_element_class_init,
168 (GInstanceInitFunc) gst_element_init,
172 _type = g_type_register_static (GST_TYPE_OBJECT, "GstElement",
173 &element_info, G_TYPE_FLAG_ABSTRACT);
175 _gst_elementclass_factory =
176 g_quark_from_static_string ("GST_ELEMENTCLASS_FACTORY");
177 g_once_init_leave (&gst_element_type, _type);
179 return gst_element_type;
183 gst_element_class_init (GstElementClass * klass)
185 GObjectClass *gobject_class;
186 GstObjectClass *gstobject_class;
188 gobject_class = (GObjectClass *) klass;
189 gstobject_class = (GstObjectClass *) klass;
191 parent_class = g_type_class_peek_parent (klass);
194 * GstElement::pad-added:
195 * @gstelement: the object which received the signal
196 * @new_pad: the pad that has been added
198 * a new #GstPad has been added to the element.
200 gst_element_signals[PAD_ADDED] =
201 g_signal_new ("pad-added", G_TYPE_FROM_CLASS (klass), G_SIGNAL_RUN_LAST,
202 G_STRUCT_OFFSET (GstElementClass, pad_added), NULL, NULL,
203 gst_marshal_VOID__OBJECT, G_TYPE_NONE, 1, GST_TYPE_PAD);
205 * GstElement::pad-removed:
206 * @gstelement: the object which received the signal
207 * @old_pad: the pad that has been removed
209 * a #GstPad has been removed from the element
211 gst_element_signals[PAD_REMOVED] =
212 g_signal_new ("pad-removed", G_TYPE_FROM_CLASS (klass), G_SIGNAL_RUN_LAST,
213 G_STRUCT_OFFSET (GstElementClass, pad_removed), NULL, NULL,
214 gst_marshal_VOID__OBJECT, G_TYPE_NONE, 1, GST_TYPE_PAD);
216 * GstElement::no-more-pads:
217 * @gstelement: the object which received the signal
219 * This signals that the element will not generate more dynamic pads.
221 gst_element_signals[NO_MORE_PADS] =
222 g_signal_new ("no-more-pads", G_TYPE_FROM_CLASS (klass),
223 G_SIGNAL_RUN_LAST, G_STRUCT_OFFSET (GstElementClass, no_more_pads), NULL,
224 NULL, gst_marshal_VOID__VOID, G_TYPE_NONE, 0);
226 gobject_class->dispose = GST_DEBUG_FUNCPTR (gst_element_dispose);
227 gobject_class->finalize = GST_DEBUG_FUNCPTR (gst_element_finalize);
229 #ifndef GST_DISABLE_LOADSAVE
230 gstobject_class->save_thyself = GST_DEBUG_FUNCPTR (gst_element_save_thyself);
231 gstobject_class->restore_thyself =
232 GST_DEBUG_FUNCPTR (gst_element_restore_thyself);
235 klass->change_state = GST_DEBUG_FUNCPTR (gst_element_change_state_func);
236 klass->set_state = GST_DEBUG_FUNCPTR (gst_element_set_state_func);
237 klass->get_state = GST_DEBUG_FUNCPTR (gst_element_get_state_func);
238 klass->set_bus = GST_DEBUG_FUNCPTR (gst_element_set_bus_func);
239 klass->query = GST_DEBUG_FUNCPTR (gst_element_default_query);
240 klass->send_event = GST_DEBUG_FUNCPTR (gst_element_default_send_event);
241 klass->numpadtemplates = 0;
243 klass->elementfactory = NULL;
247 gst_element_base_class_init (gpointer g_class)
249 GstElementClass *element_class = GST_ELEMENT_CLASS (g_class);
251 /* FIXME 0.11: Copy the element details and instead of clearing the
252 * pad template list copy the list and increase the refcount of
253 * the pad templates by one.
255 * This will make it possible to add pad templates and set element
256 * details in the class_init functions and is the real GObject way
258 * See http://bugzilla.gnome.org/show_bug.cgi?id=491501
260 memset (&element_class->details, 0, sizeof (GstElementDetails));
261 element_class->padtemplates = NULL;
263 /* set the factory, see gst_element_register() */
264 element_class->elementfactory =
265 g_type_get_qdata (G_TYPE_FROM_CLASS (element_class),
266 _gst_elementclass_factory);
267 GST_DEBUG ("type %s : factory %p", G_OBJECT_CLASS_NAME (element_class),
268 element_class->elementfactory);
272 gst_element_base_class_finalize (gpointer g_class)
274 GstElementClass *klass = GST_ELEMENT_CLASS (g_class);
276 g_list_foreach (klass->padtemplates, (GFunc) gst_object_unref, NULL);
277 g_list_free (klass->padtemplates);
278 __gst_element_details_clear (&klass->details);
282 gst_element_init (GstElement * element)
284 GST_STATE (element) = GST_STATE_NULL;
285 GST_STATE_TARGET (element) = GST_STATE_NULL;
286 GST_STATE_NEXT (element) = GST_STATE_VOID_PENDING;
287 GST_STATE_PENDING (element) = GST_STATE_VOID_PENDING;
288 GST_STATE_RETURN (element) = GST_STATE_CHANGE_SUCCESS;
290 element->state_lock = g_new0 (GStaticRecMutex, 1);
291 g_static_rec_mutex_init (element->state_lock);
292 element->state_cond = g_cond_new ();
296 * gst_element_default_error:
297 * @object: a #GObject that signalled the error.
298 * @orig: the #GstObject that initiated the error.
299 * @error: the GError.
300 * @debug: an additional debug information string, or %NULL.
302 * A default error signal callback to attach to an element.
303 * The user data passed to the g_signal_connect is ignored.
305 * The default handler will simply print the error string using g_print.
310 gst_element_default_error (GObject * object, GstObject * source, GError * error,
313 gchar *name = gst_object_get_path_string (source);
315 g_print (_("ERROR: from element %s: %s\n"), name, error->message);
317 g_print (_("Additional debug info:\n%s\n"), debug);
323 * gst_element_release_request_pad:
324 * @element: a #GstElement to release the request pad of.
325 * @pad: the #GstPad to release.
327 * Makes the element free the previously requested pad as obtained
328 * with gst_element_get_request_pad().
330 * This does not unref the pad. If the pad was created by using
331 * gst_element_get_request_pad(), gst_element_release_request_pad() needs to be
332 * followed by gst_object_unref() to free the @pad.
337 gst_element_release_request_pad (GstElement * element, GstPad * pad)
339 GstElementClass *oclass;
341 g_return_if_fail (GST_IS_ELEMENT (element));
342 g_return_if_fail (GST_IS_PAD (pad));
344 oclass = GST_ELEMENT_GET_CLASS (element);
346 /* if the element implements a custom release function we call that, else we
347 * simply remove the pad from the element */
348 if (oclass->release_pad)
349 (oclass->release_pad) (element, pad);
351 gst_element_remove_pad (element, pad);
355 * gst_element_requires_clock:
356 * @element: a #GstElement to query
358 * Query if the element requires a clock.
360 * Returns: %TRUE if the element requires a clock
365 gst_element_requires_clock (GstElement * element)
369 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
371 result = (GST_ELEMENT_GET_CLASS (element)->set_clock != NULL);
377 * gst_element_provides_clock:
378 * @element: a #GstElement to query
380 * Query if the element provides a clock. A #GstClock provided by an
381 * element can be used as the global #GstClock for the pipeline.
382 * An element that can provide a clock is only required to do so in the PAUSED
383 * state, this means when it is fully negotiated and has allocated the resources
384 * to operate the clock.
386 * Returns: %TRUE if the element provides a clock
391 gst_element_provides_clock (GstElement * element)
395 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
397 result = (GST_ELEMENT_GET_CLASS (element)->provide_clock != NULL);
403 * gst_element_provide_clock:
404 * @element: a #GstElement to query
406 * Get the clock provided by the given element.
407 * <note>An element is only required to provide a clock in the PAUSED
408 * state. Some elements can provide a clock in other states.</note>
410 * Returns: the GstClock provided by the element or %NULL
411 * if no clock could be provided. Unref after usage.
416 gst_element_provide_clock (GstElement * element)
418 GstClock *result = NULL;
419 GstElementClass *oclass;
421 g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
423 oclass = GST_ELEMENT_GET_CLASS (element);
425 if (oclass->provide_clock)
426 result = oclass->provide_clock (element);
432 * gst_element_set_clock:
433 * @element: a #GstElement to set the clock for.
434 * @clock: the #GstClock to set for the element.
436 * Sets the clock for the element. This function increases the
437 * refcount on the clock. Any previously set clock on the object
440 * Returns: %TRUE if the element accepted the clock. An element can refuse a
441 * clock when it, for example, is not able to slave its internal clock to the
442 * @clock or when it requires a specific clock to operate.
447 gst_element_set_clock (GstElement * element, GstClock * clock)
449 GstElementClass *oclass;
453 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
454 g_return_val_if_fail (clock == NULL || GST_IS_CLOCK (clock), FALSE);
456 oclass = GST_ELEMENT_GET_CLASS (element);
458 GST_CAT_DEBUG_OBJECT (GST_CAT_CLOCK, element, "setting clock %p", clock);
460 if (oclass->set_clock)
461 res = oclass->set_clock (element, clock);
464 /* only update the clock pointer if the element accepted the clock */
465 GST_OBJECT_LOCK (element);
466 clock_p = &element->clock;
467 gst_object_replace ((GstObject **) clock_p, (GstObject *) clock);
468 GST_OBJECT_UNLOCK (element);
474 * gst_element_get_clock:
475 * @element: a #GstElement to get the clock of.
477 * Gets the currently configured clock of the element. This is the clock as was
478 * last set with gst_element_set_clock().
480 * Returns: the #GstClock of the element. unref after usage.
485 gst_element_get_clock (GstElement * element)
489 g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
491 GST_OBJECT_LOCK (element);
492 if ((result = element->clock))
493 gst_object_ref (result);
494 GST_OBJECT_UNLOCK (element);
500 * gst_element_set_base_time:
501 * @element: a #GstElement.
502 * @time: the base time to set.
504 * Set the base time of an element. See gst_element_get_base_time().
509 gst_element_set_base_time (GstElement * element, GstClockTime time)
513 g_return_if_fail (GST_IS_ELEMENT (element));
515 GST_OBJECT_LOCK (element);
516 old = element->base_time;
517 element->base_time = time;
518 GST_OBJECT_UNLOCK (element);
520 GST_CAT_DEBUG_OBJECT (GST_CAT_CLOCK, element,
521 "set base_time=%" GST_TIME_FORMAT ", old %" GST_TIME_FORMAT,
522 GST_TIME_ARGS (time), GST_TIME_ARGS (old));
526 * gst_element_get_base_time:
527 * @element: a #GstElement.
529 * Returns the base time of the element. The base time is the
530 * absolute time of the clock when this element was last put to
531 * PLAYING. Subtracting the base time from the clock time gives
532 * the running time of the element.
534 * Returns: the base time of the element.
539 gst_element_get_base_time (GstElement * element)
543 g_return_val_if_fail (GST_IS_ELEMENT (element), GST_CLOCK_TIME_NONE);
545 GST_OBJECT_LOCK (element);
546 result = element->base_time;
547 GST_OBJECT_UNLOCK (element);
553 * gst_element_set_start_time:
554 * @element: a #GstElement.
555 * @time: the base time to set.
557 * Set the start time of an element. The start time of the element is the
558 * running time of the element when it last went to the PAUSED state. In READY
559 * or after a flushing seek, it is set to 0.
561 * Toplevel elements like #GstPipeline will manage the start_time and
562 * base_time on its children. Setting the start_time to #GST_CLOCK_TIME_NONE
563 * on such a toplevel element will disable the distribution of the base_time to
564 * the children and can be useful if the application manages the base_time
565 * itself, for example if you want to synchronize capture from multiple
566 * pipelines, and you can also ensure that the pipelines have the same clock.
573 gst_element_set_start_time (GstElement * element, GstClockTime time)
577 g_return_if_fail (GST_IS_ELEMENT (element));
579 GST_OBJECT_LOCK (element);
580 old = GST_ELEMENT_START_TIME (element);
581 GST_ELEMENT_START_TIME (element) = time;
582 GST_OBJECT_UNLOCK (element);
584 GST_CAT_DEBUG_OBJECT (GST_CAT_CLOCK, element,
585 "set start_time=%" GST_TIME_FORMAT ", old %" GST_TIME_FORMAT,
586 GST_TIME_ARGS (time), GST_TIME_ARGS (old));
590 * gst_element_get_start_time:
591 * @element: a #GstElement.
593 * Returns the start time of the element. The start time is the
594 * running time of the clock when this element was last put to PAUSED.
596 * Usually the start_time is managed by a toplevel element such as
601 * Returns: the start time of the element.
606 gst_element_get_start_time (GstElement * element)
610 g_return_val_if_fail (GST_IS_ELEMENT (element), GST_CLOCK_TIME_NONE);
612 GST_OBJECT_LOCK (element);
613 result = GST_ELEMENT_START_TIME (element);
614 GST_OBJECT_UNLOCK (element);
620 * gst_element_is_indexable:
621 * @element: a #GstElement.
623 * Queries if the element can be indexed.
625 * Returns: TRUE if the element can be indexed.
630 gst_element_is_indexable (GstElement * element)
634 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
636 result = (GST_ELEMENT_GET_CLASS (element)->set_index != NULL);
642 * gst_element_set_index:
643 * @element: a #GstElement.
644 * @index: a #GstIndex.
646 * Set @index on the element. The refcount of the index
647 * will be increased, any previously set index is unreffed.
652 gst_element_set_index (GstElement * element, GstIndex * index)
654 GstElementClass *oclass;
656 g_return_if_fail (GST_IS_ELEMENT (element));
657 g_return_if_fail (index == NULL || GST_IS_INDEX (index));
659 oclass = GST_ELEMENT_GET_CLASS (element);
661 if (oclass->set_index)
662 oclass->set_index (element, index);
666 * gst_element_get_index:
667 * @element: a #GstElement.
669 * Gets the index from the element.
671 * Returns: a #GstIndex or %NULL when no index was set on the
672 * element. unref after usage.
677 gst_element_get_index (GstElement * element)
679 GstElementClass *oclass;
680 GstIndex *result = NULL;
682 g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
684 oclass = GST_ELEMENT_GET_CLASS (element);
686 if (oclass->get_index)
687 result = oclass->get_index (element);
693 * gst_element_add_pad:
694 * @element: a #GstElement to add the pad to.
695 * @pad: the #GstPad to add to the element.
697 * Adds a pad (link point) to @element. @pad's parent will be set to @element;
698 * see gst_object_set_parent() for refcounting information.
700 * Pads are not automatically activated so elements should perform the needed
701 * steps to activate the pad in case this pad is added in the PAUSED or PLAYING
702 * state. See gst_pad_set_active() for more information about activating pads.
704 * The pad and the element should be unlocked when calling this function.
706 * This function will emit the #GstElement::pad-added signal on the element.
708 * Returns: %TRUE if the pad could be added. This function can fail when
709 * a pad with the same name already existed or the pad already had another
715 gst_element_add_pad (GstElement * element, GstPad * pad)
720 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
721 g_return_val_if_fail (GST_IS_PAD (pad), FALSE);
723 /* locking pad to look at the name */
724 GST_OBJECT_LOCK (pad);
725 pad_name = g_strdup (GST_PAD_NAME (pad));
726 GST_CAT_INFO_OBJECT (GST_CAT_ELEMENT_PADS, element, "adding pad '%s'",
727 GST_STR_NULL (pad_name));
728 flushing = GST_PAD_IS_FLUSHING (pad);
729 GST_OBJECT_UNLOCK (pad);
731 /* then check to see if there's already a pad by that name here */
732 GST_OBJECT_LOCK (element);
733 if (G_UNLIKELY (!gst_object_check_uniqueness (element->pads, pad_name)))
736 /* try to set the pad's parent */
737 if (G_UNLIKELY (!gst_object_set_parent (GST_OBJECT_CAST (pad),
738 GST_OBJECT_CAST (element))))
741 /* check for flushing pads */
742 if (flushing && (GST_STATE (element) > GST_STATE_READY ||
743 GST_STATE_NEXT (element) == GST_STATE_PAUSED)) {
744 g_warning ("adding flushing pad '%s' to running element '%s'",
745 GST_STR_NULL (pad_name), GST_ELEMENT_NAME (element));
747 GST_OBJECT_LOCK (pad);
748 GST_PAD_UNSET_FLUSHING (pad);
749 GST_OBJECT_UNLOCK (pad);
754 /* add it to the list */
755 switch (gst_pad_get_direction (pad)) {
757 element->srcpads = g_list_prepend (element->srcpads, pad);
758 element->numsrcpads++;
761 element->sinkpads = g_list_prepend (element->sinkpads, pad);
762 element->numsinkpads++;
767 element->pads = g_list_prepend (element->pads, pad);
769 element->pads_cookie++;
770 GST_OBJECT_UNLOCK (element);
772 /* emit the PAD_ADDED signal */
773 g_signal_emit (element, gst_element_signals[PAD_ADDED], 0, pad);
780 g_critical ("Padname %s is not unique in element %s, not adding",
781 pad_name, GST_ELEMENT_NAME (element));
782 GST_OBJECT_UNLOCK (element);
789 ("Pad %s already has parent when trying to add to element %s",
790 pad_name, GST_ELEMENT_NAME (element));
791 GST_OBJECT_UNLOCK (element);
797 GST_OBJECT_LOCK (pad);
799 ("Trying to add pad %s to element %s, but it has no direction",
800 GST_OBJECT_NAME (pad), GST_ELEMENT_NAME (element));
801 GST_OBJECT_UNLOCK (pad);
802 GST_OBJECT_UNLOCK (element);
808 * gst_element_remove_pad:
809 * @element: a #GstElement to remove pad from.
810 * @pad: the #GstPad to remove from the element.
812 * Removes @pad from @element. @pad will be destroyed if it has not been
813 * referenced elsewhere using gst_object_unparent().
815 * This function is used by plugin developers and should not be used
816 * by applications. Pads that were dynamically requested from elements
817 * with gst_element_get_request_pad() should be released with the
818 * gst_element_release_request_pad() function instead.
820 * Pads are not automatically deactivated so elements should perform the needed
821 * steps to deactivate the pad in case this pad is removed in the PAUSED or
822 * PLAYING state. See gst_pad_set_active() for more information about
825 * The pad and the element should be unlocked when calling this function.
827 * This function will emit the #GstElement::pad-removed signal on the element.
829 * Returns: %TRUE if the pad could be removed. Can return %FALSE if the
830 * pad does not belong to the provided element.
835 gst_element_remove_pad (GstElement * element, GstPad * pad)
839 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
840 g_return_val_if_fail (GST_IS_PAD (pad), FALSE);
842 /* locking pad to look at the name and parent */
843 GST_OBJECT_LOCK (pad);
844 GST_CAT_INFO_OBJECT (GST_CAT_ELEMENT_PADS, element, "removing pad '%s'",
845 GST_STR_NULL (GST_PAD_NAME (pad)));
847 if (G_UNLIKELY (GST_PAD_PARENT (pad) != element))
849 GST_OBJECT_UNLOCK (pad);
852 if ((peer = gst_pad_get_peer (pad))) {
853 /* window for MT unsafeness, someone else could unlink here
854 * and then we call unlink with wrong pads. The unlink
855 * function would catch this and safely return failed. */
856 if (GST_PAD_IS_SRC (pad))
857 gst_pad_unlink (pad, peer);
859 gst_pad_unlink (peer, pad);
861 gst_object_unref (peer);
864 GST_OBJECT_LOCK (element);
865 /* remove it from the list */
866 switch (gst_pad_get_direction (pad)) {
868 element->srcpads = g_list_remove (element->srcpads, pad);
869 element->numsrcpads--;
872 element->sinkpads = g_list_remove (element->sinkpads, pad);
873 element->numsinkpads--;
876 g_critical ("Removing pad without direction???");
879 element->pads = g_list_remove (element->pads, pad);
881 element->pads_cookie++;
882 GST_OBJECT_UNLOCK (element);
884 /* emit the PAD_REMOVED signal before unparenting and losing the last ref. */
885 g_signal_emit (element, gst_element_signals[PAD_REMOVED], 0, pad);
887 gst_object_unparent (GST_OBJECT_CAST (pad));
894 /* FIXME, locking order? */
895 GST_OBJECT_LOCK (element);
896 g_critical ("Padname %s:%s does not belong to element %s when removing",
897 GST_DEBUG_PAD_NAME (pad), GST_ELEMENT_NAME (element));
898 GST_OBJECT_UNLOCK (element);
899 GST_OBJECT_UNLOCK (pad);
905 * gst_element_no_more_pads:
906 * @element: a #GstElement
908 * Use this function to signal that the element does not expect any more pads
909 * to show up in the current pipeline. This function should be called whenever
910 * pads have been added by the element itself. Elements with #GST_PAD_SOMETIMES
911 * pad templates use this in combination with autopluggers to figure out that
912 * the element is done initializing its pads.
914 * This function emits the #GstElement::no-more-pads signal.
919 gst_element_no_more_pads (GstElement * element)
921 g_return_if_fail (GST_IS_ELEMENT (element));
923 g_signal_emit (element, gst_element_signals[NO_MORE_PADS], 0);
927 pad_compare_name (GstPad * pad1, const gchar * name)
931 GST_OBJECT_LOCK (pad1);
932 result = strcmp (GST_PAD_NAME (pad1), name);
933 GST_OBJECT_UNLOCK (pad1);
939 * gst_element_get_static_pad:
940 * @element: a #GstElement to find a static pad of.
941 * @name: the name of the static #GstPad to retrieve.
943 * Retrieves a pad from @element by name. This version only retrieves
944 * already-existing (i.e. 'static') pads.
946 * Returns: the requested #GstPad if found, otherwise %NULL. unref after
952 gst_element_get_static_pad (GstElement * element, const gchar * name)
955 GstPad *result = NULL;
957 g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
958 g_return_val_if_fail (name != NULL, NULL);
960 GST_OBJECT_LOCK (element);
962 g_list_find_custom (element->pads, name, (GCompareFunc) pad_compare_name);
964 result = GST_PAD_CAST (find->data);
965 gst_object_ref (result);
968 if (result == NULL) {
969 GST_CAT_INFO (GST_CAT_ELEMENT_PADS, "no such pad '%s' in element \"%s\"",
970 name, GST_ELEMENT_NAME (element));
972 GST_CAT_INFO (GST_CAT_ELEMENT_PADS, "found pad %s:%s",
973 GST_ELEMENT_NAME (element), name);
975 GST_OBJECT_UNLOCK (element);
981 gst_element_request_pad (GstElement * element, GstPadTemplate * templ,
984 GstPad *newpad = NULL;
985 GstElementClass *oclass;
987 oclass = GST_ELEMENT_GET_CLASS (element);
989 if (oclass->request_new_pad)
990 newpad = (oclass->request_new_pad) (element, templ, name);
993 gst_object_ref (newpad);
999 * gst_element_get_request_pad:
1000 * @element: a #GstElement to find a request pad of.
1001 * @name: the name of the request #GstPad to retrieve.
1003 * Retrieves a pad from the element by name. This version only retrieves
1004 * request pads. The pad should be released with
1005 * gst_element_release_request_pad().
1007 * Returns: requested #GstPad if found, otherwise %NULL. Release after usage.
1010 gst_element_get_request_pad (GstElement * element, const gchar * name)
1012 GstPadTemplate *templ = NULL;
1014 const gchar *req_name = NULL;
1015 gboolean templ_found = FALSE;
1019 gchar *str, *endptr = NULL;
1020 GstElementClass *class;
1022 g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
1023 g_return_val_if_fail (name != NULL, NULL);
1025 class = GST_ELEMENT_GET_CLASS (element);
1027 /* if the name contains a %, we assume it's the complete template name. Get
1028 * the template and try to get a pad */
1029 if (strstr (name, "%")) {
1030 templ = gst_element_class_get_request_pad_template (class, name);
1035 /* there is no % in the name, try to find a matching template */
1036 list = gst_element_class_get_pad_template_list (class);
1037 while (!templ_found && list) {
1038 templ = (GstPadTemplate *) list->data;
1039 if (templ->presence == GST_PAD_REQUEST) {
1040 GST_CAT_DEBUG (GST_CAT_PADS, "comparing %s to %s", name,
1041 templ->name_template);
1042 /* see if we find an exact match */
1043 if (strcmp (name, templ->name_template) == 0) {
1048 /* Because of sanity checks in gst_pad_template_new(), we know that %s
1049 and %d, occurring at the end of the name_template, are the only
1051 else if ((str = strchr (templ->name_template, '%'))
1052 && strncmp (templ->name_template, name,
1053 str - templ->name_template) == 0
1054 && strlen (name) > str - templ->name_template) {
1055 data = name + (str - templ->name_template);
1056 if (*(str + 1) == 'd') {
1058 n = (gint) strtol (data, &endptr, 10);
1059 if (endptr && *endptr == '\0') {
1079 pad = gst_element_request_pad (element, templ, req_name);
1085 * gst_element_get_pad:
1086 * @element: a #GstElement.
1087 * @name: the name of the pad to retrieve.
1089 * Retrieves a pad from @element by name. Tries gst_element_get_static_pad()
1090 * first, then gst_element_get_request_pad().
1092 * Deprecated: This function is deprecated as it's unclear if the reference
1093 * to the result pad should be released with gst_object_unref() in case of a static pad
1094 * or gst_element_release_request_pad() in case of a request pad.
1095 * Use gst_element_get_static_pad() or gst_element_get_request_pad() instead.
1097 * Returns: the #GstPad if found, otherwise %NULL. Unref or Release after usage,
1098 * depending on the type of the pad.
1100 #ifndef GST_REMOVE_DEPRECATED
1102 gst_element_get_pad (GstElement * element, const gchar * name)
1106 g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
1107 g_return_val_if_fail (name != NULL, NULL);
1109 pad = gst_element_get_static_pad (element, name);
1111 pad = gst_element_get_request_pad (element, name);
1115 #endif /* GST_REMOVE_DEPRECATED */
1117 static GstIteratorItem
1118 iterate_pad (GstIterator * it, GstPad * pad)
1120 gst_object_ref (pad);
1121 return GST_ITERATOR_ITEM_PASS;
1124 static GstIterator *
1125 gst_element_iterate_pad_list (GstElement * element, GList ** padlist)
1127 GstIterator *result;
1129 GST_OBJECT_LOCK (element);
1130 gst_object_ref (element);
1131 result = gst_iterator_new_list (GST_TYPE_PAD,
1132 GST_OBJECT_GET_LOCK (element),
1133 &element->pads_cookie,
1136 (GstIteratorItemFunction) iterate_pad,
1137 (GstIteratorDisposeFunction) gst_object_unref);
1138 GST_OBJECT_UNLOCK (element);
1144 * gst_element_iterate_pads:
1145 * @element: a #GstElement to iterate pads of.
1147 * Retrieves an iterattor of @element's pads. The iterator should
1148 * be freed after usage.
1150 * Returns: the #GstIterator of #GstPad. Unref each pad after use.
1155 gst_element_iterate_pads (GstElement * element)
1157 g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
1159 return gst_element_iterate_pad_list (element, &element->pads);
1163 * gst_element_iterate_src_pads:
1164 * @element: a #GstElement.
1166 * Retrieves an iterator of @element's source pads.
1168 * Returns: the #GstIterator of #GstPad. Unref each pad after use.
1173 gst_element_iterate_src_pads (GstElement * element)
1175 g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
1177 return gst_element_iterate_pad_list (element, &element->srcpads);
1181 * gst_element_iterate_sink_pads:
1182 * @element: a #GstElement.
1184 * Retrieves an iterator of @element's sink pads.
1186 * Returns: the #GstIterator of #GstPad. Unref each pad after use.
1191 gst_element_iterate_sink_pads (GstElement * element)
1193 g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
1195 return gst_element_iterate_pad_list (element, &element->sinkpads);
1199 * gst_element_class_add_pad_template:
1200 * @klass: the #GstElementClass to add the pad template to.
1201 * @templ: a #GstPadTemplate to add to the element class.
1203 * Adds a padtemplate to an element class. This is mainly used in the _base_init
1204 * functions of classes.
1207 gst_element_class_add_pad_template (GstElementClass * klass,
1208 GstPadTemplate * templ)
1210 g_return_if_fail (GST_IS_ELEMENT_CLASS (klass));
1211 g_return_if_fail (GST_IS_PAD_TEMPLATE (templ));
1213 /* FIXME 0.11: allow replacing the pad templates by
1214 * calling this with the same name as an already existing pad
1215 * template. For this we _must_ _not_ ref the added pad template
1216 * a second time and _must_ document that this function takes
1217 * ownership of the pad template. Otherwise we will leak pad templates
1218 * or the caller unref's the pad template and it disappears */
1219 /* avoid registering pad templates with the same name */
1220 g_return_if_fail (gst_element_class_get_pad_template (klass,
1221 templ->name_template) == NULL);
1223 klass->padtemplates = g_list_append (klass->padtemplates,
1224 gst_object_ref (templ));
1225 klass->numpadtemplates++;
1229 * gst_element_class_set_details:
1230 * @klass: class to set details for
1231 * @details: details to set
1233 * Sets the detailed information for a #GstElementClass.
1234 * <note>This function is for use in _base_init functions only.</note>
1236 * The @details are copied.
1239 gst_element_class_set_details (GstElementClass * klass,
1240 const GstElementDetails * details)
1242 g_return_if_fail (GST_IS_ELEMENT_CLASS (klass));
1243 g_return_if_fail (GST_IS_ELEMENT_DETAILS (details));
1245 __gst_element_details_copy (&klass->details, details);
1249 * gst_element_class_set_details_simple:
1250 * @klass: class to set details for
1251 * @longname: The long English name of the element. E.g. "File Sink"
1252 * @classification: String describing the type of element, as an unordered list
1253 * separated with slashes ('/'). See draft-klass.txt of the design docs
1254 * for more details and common types. E.g: "Sink/File"
1255 * @description: Sentence describing the purpose of the element.
1256 * E.g: "Write stream to a file"
1257 * @author: Name and contact details of the author(s). Use \n to separate
1258 * multiple author details. E.g: "Joe Bloggs <joe.blogs at foo.com>"
1260 * Sets the detailed information for a #GstElementClass. Simpler version of
1261 * gst_element_class_set_details() that generates less linker overhead.
1262 * <note>This function is for use in _base_init functions only.</note>
1264 * The detail parameter strings are copied into the #GstElementDetails for
1265 * the element class.
1270 gst_element_class_set_details_simple (GstElementClass * klass,
1271 const gchar * longname, const gchar * classification,
1272 const gchar * description, const gchar * author)
1274 const GstElementDetails details =
1275 GST_ELEMENT_DETAILS ((gchar *) longname, (gchar *) classification,
1276 (gchar *) description, (gchar *) author);
1278 g_return_if_fail (GST_IS_ELEMENT_CLASS (klass));
1280 __gst_element_details_copy (&klass->details, &details);
1284 * gst_element_class_get_pad_template_list:
1285 * @element_class: a #GstElementClass to get pad templates of.
1287 * Retrieves a list of the pad templates associated with @element_class. The
1288 * list must not be modified by the calling code.
1289 * <note>If you use this function in the #GInstanceInitFunc of an object class
1290 * that has subclasses, make sure to pass the g_class parameter of the
1291 * #GInstanceInitFunc here.</note>
1293 * Returns: the #GList of padtemplates.
1296 gst_element_class_get_pad_template_list (GstElementClass * element_class)
1298 g_return_val_if_fail (GST_IS_ELEMENT_CLASS (element_class), NULL);
1300 return element_class->padtemplates;
1304 * gst_element_class_get_pad_template:
1305 * @element_class: a #GstElementClass to get the pad template of.
1306 * @name: the name of the #GstPadTemplate to get.
1308 * Retrieves a padtemplate from @element_class with the given name.
1309 * <note>If you use this function in the #GInstanceInitFunc of an object class
1310 * that has subclasses, make sure to pass the g_class parameter of the
1311 * #GInstanceInitFunc here.</note>
1313 * Returns: the #GstPadTemplate with the given name, or %NULL if none was found.
1314 * No unreferencing is necessary.
1317 gst_element_class_get_pad_template (GstElementClass * element_class,
1322 g_return_val_if_fail (GST_IS_ELEMENT_CLASS (element_class), NULL);
1323 g_return_val_if_fail (name != NULL, NULL);
1325 padlist = gst_element_class_get_pad_template_list (element_class);
1328 GstPadTemplate *padtempl = (GstPadTemplate *) padlist->data;
1330 if (strcmp (padtempl->name_template, name) == 0)
1333 padlist = g_list_next (padlist);
1339 static GstPadTemplate *
1340 gst_element_class_get_request_pad_template (GstElementClass * element_class,
1343 GstPadTemplate *tmpl;
1345 tmpl = gst_element_class_get_pad_template (element_class, name);
1346 if (tmpl != NULL && tmpl->presence == GST_PAD_REQUEST)
1352 /* get a random pad on element of the given direction.
1353 * The pad is random in a sense that it is the first pad that is (optionaly) linked.
1356 gst_element_get_random_pad (GstElement * element, gboolean need_linked,
1357 GstPadDirection dir)
1359 GstPad *result = NULL;
1362 GST_CAT_DEBUG (GST_CAT_ELEMENT_PADS, "getting a random pad");
1366 GST_OBJECT_LOCK (element);
1367 pads = element->srcpads;
1370 GST_OBJECT_LOCK (element);
1371 pads = element->sinkpads;
1374 goto wrong_direction;
1376 for (; pads; pads = g_list_next (pads)) {
1377 GstPad *pad = GST_PAD_CAST (pads->data);
1379 GST_OBJECT_LOCK (pad);
1380 GST_CAT_DEBUG (GST_CAT_ELEMENT_PADS, "checking pad %s:%s",
1381 GST_DEBUG_PAD_NAME (pad));
1383 if (need_linked && !GST_PAD_IS_LINKED (pad)) {
1384 /* if we require a linked pad, and it is not linked, continue the
1386 GST_CAT_DEBUG (GST_CAT_ELEMENT_PADS, "pad %s:%s is not linked",
1387 GST_DEBUG_PAD_NAME (pad));
1388 GST_OBJECT_UNLOCK (pad);
1391 /* found a pad, stop search */
1392 GST_CAT_DEBUG (GST_CAT_ELEMENT_PADS, "found pad %s:%s",
1393 GST_DEBUG_PAD_NAME (pad));
1394 GST_OBJECT_UNLOCK (pad);
1400 gst_object_ref (result);
1402 GST_OBJECT_UNLOCK (element);
1406 /* ERROR handling */
1409 g_warning ("unknown pad direction %d", dir);
1415 gst_element_default_send_event (GstElement * element, GstEvent * event)
1417 gboolean result = FALSE;
1420 pad = GST_EVENT_IS_DOWNSTREAM (event) ?
1421 gst_element_get_random_pad (element, TRUE, GST_PAD_SRC) :
1422 gst_element_get_random_pad (element, TRUE, GST_PAD_SINK);
1425 GST_CAT_DEBUG (GST_CAT_ELEMENT_PADS,
1426 "pushing %s event to random %s pad %s:%s",
1427 GST_EVENT_TYPE_NAME (event),
1428 (GST_PAD_DIRECTION (pad) == GST_PAD_SRC ? "src" : "sink"),
1429 GST_DEBUG_PAD_NAME (pad));
1431 result = gst_pad_push_event (pad, event);
1432 gst_object_unref (pad);
1434 GST_CAT_INFO (GST_CAT_ELEMENT_PADS, "can't send %s event on element %s",
1435 GST_EVENT_TYPE_NAME (event), GST_ELEMENT_NAME (element));
1441 * gst_element_send_event:
1442 * @element: a #GstElement to send the event to.
1443 * @event: the #GstEvent to send to the element.
1445 * Sends an event to an element. If the element doesn't implement an
1446 * event handler, the event will be pushed on a random linked sink pad for
1447 * upstream events or a random linked source pad for downstream events.
1449 * This function takes owership of the provided event so you should
1450 * gst_event_ref() it if you want to reuse the event after this call.
1452 * Returns: %TRUE if the event was handled.
1457 gst_element_send_event (GstElement * element, GstEvent * event)
1459 GstElementClass *oclass;
1460 gboolean result = FALSE;
1462 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
1463 g_return_val_if_fail (event != NULL, FALSE);
1465 oclass = GST_ELEMENT_GET_CLASS (element);
1467 GST_STATE_LOCK (element);
1468 if (oclass->send_event) {
1469 GST_CAT_DEBUG (GST_CAT_ELEMENT_PADS, "send %s event on element %s",
1470 GST_EVENT_TYPE_NAME (event), GST_ELEMENT_NAME (element));
1471 result = oclass->send_event (element, event);
1473 result = gst_element_default_send_event (element, event);
1475 GST_STATE_UNLOCK (element);
1482 * @element: a #GstElement to send the event to.
1483 * @rate: The new playback rate
1484 * @format: The format of the seek values
1485 * @flags: The optional seek flags.
1486 * @cur_type: The type and flags for the new current position
1487 * @cur: The value of the new current position
1488 * @stop_type: The type and flags for the new stop position
1489 * @stop: The value of the new stop position
1491 * Sends a seek event to an element. See gst_event_new_seek() for the details of
1492 * the parameters. The seek event is sent to the element using
1493 * gst_element_send_event().
1495 * Returns: %TRUE if the event was handled.
1500 gst_element_seek (GstElement * element, gdouble rate, GstFormat format,
1501 GstSeekFlags flags, GstSeekType cur_type, gint64 cur,
1502 GstSeekType stop_type, gint64 stop)
1507 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
1510 gst_event_new_seek (rate, format, flags, cur_type, cur, stop_type, stop);
1511 result = gst_element_send_event (element, event);
1517 * gst_element_get_query_types:
1518 * @element: a #GstElement to query
1520 * Get an array of query types from the element.
1521 * If the element doesn't implement a query types function,
1522 * the query will be forwarded to the peer of a random linked sink pad.
1524 * Returns: An array of #GstQueryType elements that should not
1525 * be freed or modified.
1529 const GstQueryType *
1530 gst_element_get_query_types (GstElement * element)
1532 GstElementClass *oclass;
1533 const GstQueryType *result = NULL;
1535 g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
1537 oclass = GST_ELEMENT_GET_CLASS (element);
1539 if (oclass->get_query_types) {
1540 result = oclass->get_query_types (element);
1542 GstPad *pad = gst_element_get_random_pad (element, TRUE, GST_PAD_SINK);
1545 GstPad *peer = gst_pad_get_peer (pad);
1548 result = gst_pad_get_query_types (peer);
1550 gst_object_unref (peer);
1552 gst_object_unref (pad);
1559 gst_element_default_query (GstElement * element, GstQuery * query)
1561 gboolean result = FALSE;
1564 pad = gst_element_get_random_pad (element, FALSE, GST_PAD_SRC);
1566 result = gst_pad_query (pad, query);
1568 gst_object_unref (pad);
1570 pad = gst_element_get_random_pad (element, TRUE, GST_PAD_SINK);
1572 GstPad *peer = gst_pad_get_peer (pad);
1575 result = gst_pad_query (peer, query);
1577 gst_object_unref (peer);
1579 gst_object_unref (pad);
1586 * gst_element_query:
1587 * @element: a #GstElement to perform the query on.
1588 * @query: the #GstQuery.
1590 * Performs a query on the given element.
1592 * For elements that don't implement a query handler, this function
1593 * forwards the query to a random srcpad or to the peer of a
1594 * random linked sinkpad of this element.
1596 * Returns: TRUE if the query could be performed.
1601 gst_element_query (GstElement * element, GstQuery * query)
1603 GstElementClass *oclass;
1604 gboolean result = FALSE;
1606 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
1607 g_return_val_if_fail (query != NULL, FALSE);
1609 oclass = GST_ELEMENT_GET_CLASS (element);
1611 if (oclass->query) {
1612 GST_CAT_DEBUG (GST_CAT_ELEMENT_PADS, "send query on element %s",
1613 GST_ELEMENT_NAME (element));
1614 result = oclass->query (element, query);
1616 result = gst_element_default_query (element, query);
1622 * gst_element_post_message:
1623 * @element: a #GstElement posting the message
1624 * @message: a #GstMessage to post
1626 * Post a message on the element's #GstBus. This function takes ownership of the
1627 * message; if you want to access the message after this call, you should add an
1628 * additional reference before calling.
1630 * Returns: %TRUE if the message was successfully posted. The function returns
1631 * %FALSE if the element did not have a bus.
1636 gst_element_post_message (GstElement * element, GstMessage * message)
1639 gboolean result = FALSE;
1641 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
1642 g_return_val_if_fail (message != NULL, FALSE);
1644 GST_OBJECT_LOCK (element);
1647 if (G_UNLIKELY (bus == NULL))
1650 gst_object_ref (bus);
1651 GST_OBJECT_UNLOCK (element);
1653 /* we release the element lock when posting the message so that any
1654 * (synchronous) message handlers can operate on the element */
1655 result = gst_bus_post (bus, message);
1656 gst_object_unref (bus);
1663 GST_CAT_DEBUG_OBJECT (GST_CAT_MESSAGE, element,
1664 "not posting message %p: no bus", message);
1665 GST_OBJECT_UNLOCK (element);
1666 gst_message_unref (message);
1672 * _gst_element_error_printf:
1673 * @format: the printf-like format to use, or %NULL
1675 * This function is only used internally by the gst_element_error() macro.
1677 * Returns: a newly allocated string, or %NULL if the format was %NULL or ""
1682 _gst_element_error_printf (const gchar * format, ...)
1692 va_start (args, format);
1693 buffer = g_strdup_vprintf (format, args);
1699 * gst_element_message_full:
1700 * @element: a #GstElement to send message from
1701 * @type: the #GstMessageType
1702 * @domain: the GStreamer GError domain this message belongs to
1703 * @code: the GError code belonging to the domain
1704 * @text: an allocated text string to be used as a replacement for the
1705 * default message connected to code, or %NULL
1706 * @debug: an allocated debug message to be used as a replacement for the
1707 * default debugging information, or %NULL
1708 * @file: the source code file where the error was generated
1709 * @function: the source code function where the error was generated
1710 * @line: the source code line where the error was generated
1712 * Post an error, warning or info message on the bus from inside an element.
1714 * @type must be of #GST_MESSAGE_ERROR, #GST_MESSAGE_WARNING or
1715 * #GST_MESSAGE_INFO.
1719 void gst_element_message_full
1720 (GstElement * element, GstMessageType type,
1721 GQuark domain, gint code, gchar * text,
1722 gchar * debug, const gchar * file, const gchar * function, gint line)
1724 GError *gerror = NULL;
1728 gboolean has_debug = TRUE;
1729 GstMessage *message = NULL;
1732 GST_CAT_DEBUG_OBJECT (GST_CAT_MESSAGE, element, "start");
1733 g_return_if_fail (GST_IS_ELEMENT (element));
1734 g_return_if_fail ((type == GST_MESSAGE_ERROR) ||
1735 (type == GST_MESSAGE_WARNING) || (type == GST_MESSAGE_INFO));
1737 /* check if we send the given text or the default error text */
1738 if ((text == NULL) || (text[0] == 0)) {
1739 /* text could have come from g_strdup_printf (""); */
1741 sent_text = gst_error_get_message (domain, code);
1745 /* construct a sent_debug with extra information from source */
1746 if ((debug == NULL) || (debug[0] == 0)) {
1747 /* debug could have come from g_strdup_printf (""); */
1751 name = gst_object_get_path_string (GST_OBJECT_CAST (element));
1753 sent_debug = g_strdup_printf ("%s(%d): %s (): %s:\n%s",
1754 file, line, function, name, debug);
1756 sent_debug = g_strdup_printf ("%s(%d): %s (): %s",
1757 file, line, function, name);
1761 /* create gerror and post message */
1762 GST_CAT_INFO_OBJECT (GST_CAT_ERROR_SYSTEM, element, "posting message: %s",
1764 gerror = g_error_new_literal (domain, code, sent_text);
1767 case GST_MESSAGE_ERROR:
1769 gst_message_new_error (GST_OBJECT_CAST (element), gerror, sent_debug);
1771 case GST_MESSAGE_WARNING:
1772 message = gst_message_new_warning (GST_OBJECT_CAST (element), gerror,
1775 case GST_MESSAGE_INFO:
1776 message = gst_message_new_info (GST_OBJECT_CAST (element), gerror,
1780 g_assert_not_reached ();
1783 gst_element_post_message (element, message);
1785 GST_CAT_INFO_OBJECT (GST_CAT_ERROR_SYSTEM, element, "posted %s message: %s",
1786 (type == GST_MESSAGE_ERROR ? "error" : "warning"), sent_text);
1789 g_error_free (gerror);
1790 g_free (sent_debug);
1795 * gst_element_is_locked_state:
1796 * @element: a #GstElement.
1798 * Checks if the state of an element is locked.
1799 * If the state of an element is locked, state changes of the parent don't
1800 * affect the element.
1801 * This way you can leave currently unused elements inside bins. Just lock their
1802 * state before changing the state from #GST_STATE_NULL.
1806 * Returns: TRUE, if the element's state is locked.
1809 gst_element_is_locked_state (GstElement * element)
1813 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
1815 GST_OBJECT_LOCK (element);
1816 result = GST_OBJECT_FLAG_IS_SET (element, GST_ELEMENT_LOCKED_STATE);
1817 GST_OBJECT_UNLOCK (element);
1823 * gst_element_set_locked_state:
1824 * @element: a #GstElement
1825 * @locked_state: TRUE to lock the element's state
1827 * Locks the state of an element, so state changes of the parent don't affect
1828 * this element anymore.
1832 * Returns: TRUE if the state was changed, FALSE if bad parameters were given
1833 * or the elements state-locking needed no change.
1836 gst_element_set_locked_state (GstElement * element, gboolean locked_state)
1840 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
1842 GST_OBJECT_LOCK (element);
1843 old = GST_OBJECT_FLAG_IS_SET (element, GST_ELEMENT_LOCKED_STATE);
1845 if (G_UNLIKELY (old == locked_state))
1849 GST_CAT_DEBUG (GST_CAT_STATES, "locking state of element %s",
1850 GST_ELEMENT_NAME (element));
1851 GST_OBJECT_FLAG_SET (element, GST_ELEMENT_LOCKED_STATE);
1853 GST_CAT_DEBUG (GST_CAT_STATES, "unlocking state of element %s",
1854 GST_ELEMENT_NAME (element));
1855 GST_OBJECT_FLAG_UNSET (element, GST_ELEMENT_LOCKED_STATE);
1857 GST_OBJECT_UNLOCK (element);
1863 GST_CAT_DEBUG (GST_CAT_STATES, "elements %s was already in locked state %d",
1864 GST_ELEMENT_NAME (element), old);
1865 GST_OBJECT_UNLOCK (element);
1872 * gst_element_sync_state_with_parent:
1873 * @element: a #GstElement.
1875 * Tries to change the state of the element to the same as its parent.
1876 * If this function returns FALSE, the state of element is undefined.
1878 * Returns: TRUE, if the element's state could be synced to the parent's state.
1883 gst_element_sync_state_with_parent (GstElement * element)
1887 GstStateChangeReturn ret;
1889 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
1891 if ((parent = GST_ELEMENT_CAST (gst_element_get_parent (element)))) {
1892 GstState parent_current, parent_pending;
1894 GST_OBJECT_LOCK (parent);
1895 parent_current = GST_STATE (parent);
1896 parent_pending = GST_STATE_PENDING (parent);
1897 GST_OBJECT_UNLOCK (parent);
1899 /* set to pending if there is one, else we set it to the current state of
1901 if (parent_pending != GST_STATE_VOID_PENDING)
1902 target = parent_pending;
1904 target = parent_current;
1906 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
1907 "syncing state (%s) to parent %s %s (%s, %s)",
1908 gst_element_state_get_name (GST_STATE (element)),
1909 GST_ELEMENT_NAME (parent), gst_element_state_get_name (target),
1910 gst_element_state_get_name (parent_current),
1911 gst_element_state_get_name (parent_pending));
1913 ret = gst_element_set_state (element, target);
1914 if (ret == GST_STATE_CHANGE_FAILURE)
1917 gst_object_unref (parent);
1921 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element, "element has no parent");
1928 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
1929 "syncing state failed (%s)",
1930 gst_element_state_change_return_get_name (ret));
1931 gst_object_unref (parent);
1937 static GstStateChangeReturn
1938 gst_element_get_state_func (GstElement * element,
1939 GstState * state, GstState * pending, GstClockTime timeout)
1941 GstStateChangeReturn ret = GST_STATE_CHANGE_FAILURE;
1942 GstState old_pending;
1944 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element, "getting state, timeout %"
1945 GST_TIME_FORMAT, GST_TIME_ARGS (timeout));
1947 GST_OBJECT_LOCK (element);
1948 ret = GST_STATE_RETURN (element);
1949 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element, "RETURN is %s",
1950 gst_element_state_change_return_get_name (ret));
1952 /* we got an error, report immediatly */
1953 if (ret == GST_STATE_CHANGE_FAILURE)
1956 /* we got no_preroll, report immediatly */
1957 if (ret == GST_STATE_CHANGE_NO_PREROLL)
1960 /* no need to wait async if we are not async */
1961 if (ret != GST_STATE_CHANGE_ASYNC)
1964 old_pending = GST_STATE_PENDING (element);
1965 if (old_pending != GST_STATE_VOID_PENDING) {
1966 GTimeVal *timeval, abstimeout;
1969 if (timeout != GST_CLOCK_TIME_NONE) {
1970 glong add = timeout / 1000;
1975 /* make timeout absolute */
1976 g_get_current_time (&abstimeout);
1977 g_time_val_add (&abstimeout, add);
1978 timeval = &abstimeout;
1982 /* get cookie to detect state changes during waiting */
1983 cookie = element->state_cookie;
1985 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element,
1986 "waiting for element to commit state");
1988 /* we have a pending state change, wait for it to complete */
1989 if (!GST_STATE_TIMED_WAIT (element, timeval)) {
1990 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element, "timed out");
1991 /* timeout triggered */
1992 ret = GST_STATE_CHANGE_ASYNC;
1994 if (cookie != element->state_cookie)
1997 /* could be success or failure */
1998 if (old_pending == GST_STATE (element)) {
1999 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element, "got success");
2000 ret = GST_STATE_CHANGE_SUCCESS;
2002 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element, "got failure");
2003 ret = GST_STATE_CHANGE_FAILURE;
2006 /* if nothing is pending anymore we can return SUCCESS */
2007 if (GST_STATE_PENDING (element) == GST_STATE_VOID_PENDING) {
2008 GST_CAT_LOG_OBJECT (GST_CAT_STATES, element, "nothing pending");
2009 ret = GST_STATE_CHANGE_SUCCESS;
2015 *state = GST_STATE (element);
2017 *pending = GST_STATE_PENDING (element);
2019 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
2020 "state current: %s, pending: %s, result: %s",
2021 gst_element_state_get_name (GST_STATE (element)),
2022 gst_element_state_get_name (GST_STATE_PENDING (element)),
2023 gst_element_state_change_return_get_name (ret));
2024 GST_OBJECT_UNLOCK (element);
2031 *state = GST_STATE_VOID_PENDING;
2033 *pending = GST_STATE_VOID_PENDING;
2035 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element, "interruped");
2037 GST_OBJECT_UNLOCK (element);
2039 return GST_STATE_CHANGE_FAILURE;
2044 * gst_element_get_state:
2045 * @element: a #GstElement to get the state of.
2046 * @state: a pointer to #GstState to hold the state. Can be %NULL.
2047 * @pending: a pointer to #GstState to hold the pending state.
2049 * @timeout: a #GstClockTime to specify the timeout for an async
2050 * state change or %GST_CLOCK_TIME_NONE for infinite timeout.
2052 * Gets the state of the element.
2054 * For elements that performed an ASYNC state change, as reported by
2055 * gst_element_set_state(), this function will block up to the
2056 * specified timeout value for the state change to complete.
2057 * If the element completes the state change or goes into
2058 * an error, this function returns immediately with a return value of
2059 * %GST_STATE_CHANGE_SUCCESS or %GST_STATE_CHANGE_FAILURE respectively.
2061 * For elements that did not return %GST_STATE_CHANGE_ASYNC, this function
2062 * returns the current and pending state immediately.
2064 * This function returns %GST_STATE_CHANGE_NO_PREROLL if the element
2065 * successfully changed its state but is not able to provide data yet.
2066 * This mostly happens for live sources that only produce data in the PLAYING
2067 * state. While the state change return is equivalent to
2068 * %GST_STATE_CHANGE_SUCCESS, it is returned to the application to signal that
2069 * some sink elements might not be able to complete their state change because
2070 * an element is not producing data to complete the preroll. When setting the
2071 * element to playing, the preroll will complete and playback will start.
2073 * Returns: %GST_STATE_CHANGE_SUCCESS if the element has no more pending state
2074 * and the last state change succeeded, %GST_STATE_CHANGE_ASYNC if the
2075 * element is still performing a state change or
2076 * %GST_STATE_CHANGE_FAILURE if the last state change failed.
2080 GstStateChangeReturn
2081 gst_element_get_state (GstElement * element,
2082 GstState * state, GstState * pending, GstClockTime timeout)
2084 GstElementClass *oclass;
2085 GstStateChangeReturn result = GST_STATE_CHANGE_FAILURE;
2087 g_return_val_if_fail (GST_IS_ELEMENT (element), GST_STATE_CHANGE_FAILURE);
2089 oclass = GST_ELEMENT_GET_CLASS (element);
2091 if (oclass->get_state)
2092 result = (oclass->get_state) (element, state, pending, timeout);
2098 * gst_element_abort_state:
2099 * @element: a #GstElement to abort the state of.
2101 * Abort the state change of the element. This function is used
2102 * by elements that do asynchronous state changes and find out
2103 * something is wrong.
2105 * This function should be called with the STATE_LOCK held.
2110 gst_element_abort_state (GstElement * element)
2114 #ifndef GST_DISABLE_GST_DEBUG
2118 g_return_if_fail (GST_IS_ELEMENT (element));
2120 GST_OBJECT_LOCK (element);
2121 pending = GST_STATE_PENDING (element);
2123 if (pending == GST_STATE_VOID_PENDING ||
2124 GST_STATE_RETURN (element) == GST_STATE_CHANGE_FAILURE)
2125 goto nothing_aborted;
2127 #ifndef GST_DISABLE_GST_DEBUG
2128 old_state = GST_STATE (element);
2130 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element,
2131 "aborting state from %s to %s", gst_element_state_get_name (old_state),
2132 gst_element_state_get_name (pending));
2136 GST_STATE_RETURN (element) = GST_STATE_CHANGE_FAILURE;
2138 GST_STATE_BROADCAST (element);
2139 GST_OBJECT_UNLOCK (element);
2145 GST_OBJECT_UNLOCK (element);
2151 * gst_element_continue_state:
2152 * @element: a #GstElement to continue the state change of.
2153 * @ret: The previous state return value
2155 * Commit the state change of the element and proceed to the next
2156 * pending state if any. This function is used
2157 * by elements that do asynchronous state changes.
2158 * The core will normally call this method automatically when an
2159 * element returned %GST_STATE_CHANGE_SUCCESS from the state change function.
2161 * If after calling this method the element still has not reached
2162 * the pending state, the next state change is performed.
2164 * This method is used internally and should normally not be called by plugins
2167 * Returns: The result of the commit state change.
2171 GstStateChangeReturn
2172 gst_element_continue_state (GstElement * element, GstStateChangeReturn ret)
2174 GstStateChangeReturn old_ret;
2175 GstState old_state, old_next;
2176 GstState current, next, pending;
2177 GstMessage *message;
2178 GstStateChange transition;
2180 GST_OBJECT_LOCK (element);
2181 old_ret = GST_STATE_RETURN (element);
2182 GST_STATE_RETURN (element) = ret;
2183 pending = GST_STATE_PENDING (element);
2185 /* check if there is something to commit */
2186 if (pending == GST_STATE_VOID_PENDING)
2187 goto nothing_pending;
2189 old_state = GST_STATE (element);
2190 /* this is the state we should go to next */
2191 old_next = GST_STATE_NEXT (element);
2192 /* update current state */
2193 current = GST_STATE (element) = old_next;
2195 /* see if we reached the final state */
2196 if (pending == current)
2199 next = GST_STATE_GET_NEXT (current, pending);
2200 transition = (GstStateChange) GST_STATE_TRANSITION (current, next);
2202 GST_STATE_NEXT (element) = next;
2204 GST_STATE_RETURN (element) = GST_STATE_CHANGE_ASYNC;
2205 GST_OBJECT_UNLOCK (element);
2207 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element,
2208 "committing state from %s to %s, pending %s, next %s",
2209 gst_element_state_get_name (old_state),
2210 gst_element_state_get_name (old_next),
2211 gst_element_state_get_name (pending), gst_element_state_get_name (next));
2213 message = gst_message_new_state_changed (GST_OBJECT_CAST (element),
2214 old_state, old_next, pending);
2215 gst_element_post_message (element, message);
2217 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element,
2218 "continue state change %s to %s, final %s",
2219 gst_element_state_get_name (current),
2220 gst_element_state_get_name (next), gst_element_state_get_name (pending));
2222 ret = gst_element_change_state (element, transition);
2228 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element, "nothing pending");
2229 GST_OBJECT_UNLOCK (element);
2234 GST_STATE_PENDING (element) = GST_STATE_VOID_PENDING;
2235 GST_STATE_NEXT (element) = GST_STATE_VOID_PENDING;
2237 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element,
2238 "completed state change to %s", gst_element_state_get_name (pending));
2239 GST_OBJECT_UNLOCK (element);
2241 /* don't post silly messages with the same state. This can happen
2242 * when an element state is changed to what it already was. For bins
2243 * this can be the result of a lost state, which we check with the
2244 * previous return value.
2245 * We do signal the cond though as a _get_state() might be blocking
2247 if (old_state != old_next || old_ret == GST_STATE_CHANGE_ASYNC) {
2248 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element,
2249 "posting state-changed %s to %s",
2250 gst_element_state_get_name (old_state),
2251 gst_element_state_get_name (old_next));
2253 gst_message_new_state_changed (GST_OBJECT_CAST (element), old_state,
2254 old_next, GST_STATE_VOID_PENDING);
2255 gst_element_post_message (element, message);
2258 GST_STATE_BROADCAST (element);
2265 * gst_element_lost_state_full:
2266 * @element: a #GstElement the state is lost of
2267 * @new_base_time: if a new base time should be distributed
2269 * Brings the element to the lost state. The current state of the
2270 * element is copied to the pending state so that any call to
2271 * gst_element_get_state() will return %GST_STATE_CHANGE_ASYNC.
2273 * An ASYNC_START message is posted with indication to distribute a new
2274 * base_time to the element when @new_base_time is %TRUE.
2275 * If the element was PLAYING, it will go to PAUSED. The element
2276 * will be restored to its PLAYING state by the parent pipeline when it
2279 * This is mostly used for elements that lost their preroll buffer
2280 * in the %GST_STATE_PAUSED or %GST_STATE_PLAYING state after a flush,
2281 * they will go to their pending state again when a new preroll buffer is
2282 * queued. This function can only be called when the element is currently
2283 * not in error or an async state change.
2285 * This function is used internally and should normally not be called from
2286 * plugins or applications.
2293 gst_element_lost_state_full (GstElement * element, gboolean new_base_time)
2295 GstState old_state, new_state;
2296 GstMessage *message;
2298 g_return_if_fail (GST_IS_ELEMENT (element));
2300 GST_OBJECT_LOCK (element);
2301 if (GST_STATE_RETURN (element) == GST_STATE_CHANGE_FAILURE)
2304 if (GST_STATE_PENDING (element) != GST_STATE_VOID_PENDING)
2305 goto only_async_start;
2307 old_state = GST_STATE (element);
2309 /* when we were PLAYING, the new state is PAUSED. We will also not
2310 * automatically go to PLAYING but let the parent bin(s) set us to PLAYING
2311 * when we preroll. */
2312 if (old_state > GST_STATE_PAUSED)
2313 new_state = GST_STATE_PAUSED;
2315 new_state = old_state;
2317 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
2318 "lost state of %s to %s", gst_element_state_get_name (old_state),
2319 gst_element_state_get_name (new_state));
2321 GST_STATE (element) = new_state;
2322 GST_STATE_NEXT (element) = new_state;
2323 GST_STATE_PENDING (element) = new_state;
2324 GST_STATE_RETURN (element) = GST_STATE_CHANGE_ASYNC;
2326 GST_ELEMENT_START_TIME (element) = 0;
2327 GST_OBJECT_UNLOCK (element);
2329 message = gst_message_new_state_changed (GST_OBJECT_CAST (element),
2330 new_state, new_state, new_state);
2331 gst_element_post_message (element, message);
2334 gst_message_new_async_start (GST_OBJECT_CAST (element), new_base_time);
2335 gst_element_post_message (element, message);
2341 GST_OBJECT_UNLOCK (element);
2346 GST_OBJECT_UNLOCK (element);
2348 message = gst_message_new_async_start (GST_OBJECT_CAST (element), TRUE);
2349 gst_element_post_message (element, message);
2355 * gst_element_lost_state:
2356 * @element: a #GstElement the state is lost of
2358 * Brings the element to the lost state. This function calls
2359 * gst_element_lost_state_full() with the new_base_time set to %TRUE.
2361 * This function is used internally and should normally not be called from
2362 * plugins or applications.
2367 gst_element_lost_state (GstElement * element)
2369 gst_element_lost_state_full (element, TRUE);
2373 * gst_element_set_state:
2374 * @element: a #GstElement to change state of.
2375 * @state: the element's new #GstState.
2377 * Sets the state of the element. This function will try to set the
2378 * requested state by going through all the intermediary states and calling
2379 * the class's state change function for each.
2381 * This function can return #GST_STATE_CHANGE_ASYNC, in which case the
2382 * element will perform the remainder of the state change asynchronously in
2384 * An application can use gst_element_get_state() to wait for the completion
2385 * of the state change or it can wait for a state change message on the bus.
2387 * State changes to %GST_STATE_READY or %GST_STATE_NULL never return
2388 * #GST_STATE_CHANGE_ASYNC.
2390 * Returns: Result of the state change using #GstStateChangeReturn.
2394 GstStateChangeReturn
2395 gst_element_set_state (GstElement * element, GstState state)
2397 GstElementClass *oclass;
2398 GstStateChangeReturn result = GST_STATE_CHANGE_FAILURE;
2400 g_return_val_if_fail (GST_IS_ELEMENT (element), GST_STATE_CHANGE_FAILURE);
2402 oclass = GST_ELEMENT_GET_CLASS (element);
2404 if (oclass->set_state)
2405 result = (oclass->set_state) (element, state);
2411 * default set state function, calculates the next state based
2412 * on current state and calls the change_state function
2414 static GstStateChangeReturn
2415 gst_element_set_state_func (GstElement * element, GstState state)
2417 GstState current, next, old_pending;
2418 GstStateChangeReturn ret;
2419 GstStateChange transition;
2420 GstStateChangeReturn old_ret;
2422 g_return_val_if_fail (GST_IS_ELEMENT (element), GST_STATE_CHANGE_FAILURE);
2424 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element, "set_state to %s",
2425 gst_element_state_get_name (state));
2427 /* state lock is taken to protect the set_state() and get_state()
2428 * procedures, it does not lock any variables. */
2429 GST_STATE_LOCK (element);
2431 /* now calculate how to get to the new state */
2432 GST_OBJECT_LOCK (element);
2433 old_ret = GST_STATE_RETURN (element);
2434 /* previous state change returned an error, remove all pending
2435 * and next states */
2436 if (old_ret == GST_STATE_CHANGE_FAILURE) {
2437 GST_STATE_NEXT (element) = GST_STATE_VOID_PENDING;
2438 GST_STATE_PENDING (element) = GST_STATE_VOID_PENDING;
2439 GST_STATE_RETURN (element) = GST_STATE_CHANGE_SUCCESS;
2442 current = GST_STATE (element);
2443 next = GST_STATE_NEXT (element);
2444 old_pending = GST_STATE_PENDING (element);
2446 /* this is the (new) state we should go to. TARGET is the last state we set on
2448 if (state != GST_STATE_TARGET (element)) {
2449 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
2450 "setting target state to %s", gst_element_state_get_name (state));
2451 GST_STATE_TARGET (element) = state;
2452 /* increment state cookie so that we can track each state change. We only do
2453 * this if this is actually a new state change. */
2454 element->state_cookie++;
2456 GST_STATE_PENDING (element) = state;
2458 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
2459 "current %s, old_pending %s, next %s, old return %s",
2460 gst_element_state_get_name (current),
2461 gst_element_state_get_name (old_pending),
2462 gst_element_state_get_name (next),
2463 gst_element_state_change_return_get_name (old_ret));
2465 /* if the element was busy doing a state change, we just update the
2466 * target state, it'll get to it async then. */
2467 if (old_pending != GST_STATE_VOID_PENDING) {
2468 /* upwards state change will happen ASYNC */
2469 if (old_pending <= state)
2471 /* element is going to this state already */
2472 else if (next == state)
2474 /* element was performing an ASYNC upward state change and
2475 * we request to go downward again. Start from the next pending
2477 else if (next > state
2478 && GST_STATE_RETURN (element) == GST_STATE_CHANGE_ASYNC) {
2482 next = GST_STATE_GET_NEXT (current, state);
2483 /* now we store the next state */
2484 GST_STATE_NEXT (element) = next;
2485 /* mark busy, we need to check that there is actually a state change
2486 * to be done else we could accidentally override SUCCESS/NO_PREROLL and
2487 * the default element change_state function has no way to know what the
2488 * old value was... could consider this a FIXME...*/
2489 if (current != next)
2490 GST_STATE_RETURN (element) = GST_STATE_CHANGE_ASYNC;
2492 transition = (GstStateChange) GST_STATE_TRANSITION (current, next);
2494 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
2495 "%s: setting state from %s to %s",
2496 (next != state ? "intermediate" : "final"),
2497 gst_element_state_get_name (current), gst_element_state_get_name (next));
2499 /* now signal any waiters, they will error since the cookie was incremented */
2500 GST_STATE_BROADCAST (element);
2502 GST_OBJECT_UNLOCK (element);
2504 ret = gst_element_change_state (element, transition);
2506 GST_STATE_UNLOCK (element);
2508 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element, "returned %s",
2509 gst_element_state_change_return_get_name (ret));
2515 GST_STATE_RETURN (element) = GST_STATE_CHANGE_ASYNC;
2516 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
2517 "element was busy with async state change");
2518 GST_OBJECT_UNLOCK (element);
2520 GST_STATE_UNLOCK (element);
2522 return GST_STATE_CHANGE_ASYNC;
2527 * gst_element_change_state:
2528 * @element: a #GstElement
2529 * @transition: the requested transition
2531 * Perform @transition on @element.
2533 * This function must be called with STATE_LOCK held and is mainly used
2536 * Returns: the #GstStateChangeReturn of the state transition.
2538 GstStateChangeReturn
2539 gst_element_change_state (GstElement * element, GstStateChange transition)
2541 GstElementClass *oclass;
2542 GstStateChangeReturn ret = GST_STATE_CHANGE_SUCCESS;
2544 oclass = GST_ELEMENT_GET_CLASS (element);
2546 /* call the state change function so it can set the state */
2547 if (oclass->change_state)
2548 ret = (oclass->change_state) (element, transition);
2550 ret = GST_STATE_CHANGE_FAILURE;
2553 case GST_STATE_CHANGE_FAILURE:
2554 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element,
2555 "have FAILURE change_state return");
2556 /* state change failure */
2557 gst_element_abort_state (element);
2559 case GST_STATE_CHANGE_ASYNC:
2563 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
2564 "element will change state ASYNC");
2566 target = GST_STATE_TARGET (element);
2568 if (target > GST_STATE_READY)
2571 /* else we just continue the state change downwards */
2572 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element,
2573 "forcing commit state %s <= %s",
2574 gst_element_state_get_name (target),
2575 gst_element_state_get_name (GST_STATE_READY));
2577 ret = gst_element_continue_state (element, GST_STATE_CHANGE_SUCCESS);
2580 case GST_STATE_CHANGE_SUCCESS:
2581 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
2582 "element changed state SUCCESS");
2583 /* we can commit the state now which will proceeed to
2585 ret = gst_element_continue_state (element, ret);
2587 case GST_STATE_CHANGE_NO_PREROLL:
2588 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
2589 "element changed state NO_PREROLL");
2590 /* we can commit the state now which will proceeed to
2592 ret = gst_element_continue_state (element, ret);
2595 goto invalid_return;
2598 GST_CAT_LOG_OBJECT (GST_CAT_STATES, element, "exit state change %d", ret);
2603 GST_CAT_LOG_OBJECT (GST_CAT_STATES, element, "exit async state change %d",
2611 GST_OBJECT_LOCK (element);
2612 /* somebody added a GST_STATE_ and forgot to do stuff here ! */
2613 g_critical ("%s: unknown return value %d from a state change function",
2614 GST_ELEMENT_NAME (element), ret);
2616 /* we are in error now */
2617 ret = GST_STATE_CHANGE_FAILURE;
2618 GST_STATE_RETURN (element) = ret;
2619 GST_OBJECT_UNLOCK (element);
2625 /* gst_iterator_fold functions for pads_activate
2626 * Note how we don't stop the iterator when we fail an activation. This is
2627 * probably a FIXME since when one pad activation fails, we don't want to
2628 * continue our state change. */
2630 activate_pads (GstPad * pad, GValue * ret, gboolean * active)
2632 if (!gst_pad_set_active (pad, *active))
2633 g_value_set_boolean (ret, FALSE);
2635 /* unref the object that was reffed for us by _fold */
2636 gst_object_unref (pad);
2640 /* set the caps on the pad to NULL */
2642 clear_caps (GstPad * pad, GValue * ret, gboolean * active)
2644 gst_pad_set_caps (pad, NULL);
2645 gst_object_unref (pad);
2649 /* returns false on error or early cutout (will never happen because the fold
2650 * function always returns TRUE, see FIXME above) of the fold, true if all
2651 * pads in @iter were (de)activated successfully. */
2653 iterator_activate_fold_with_resync (GstIterator * iter,
2654 GstIteratorFoldFunction func, gpointer user_data)
2656 GstIteratorResult ires;
2659 /* no need to unset this later, it's just a boolean */
2660 g_value_init (&ret, G_TYPE_BOOLEAN);
2661 g_value_set_boolean (&ret, TRUE);
2664 ires = gst_iterator_fold (iter, func, &ret, user_data);
2666 case GST_ITERATOR_RESYNC:
2667 /* need to reset the result again */
2668 g_value_set_boolean (&ret, TRUE);
2669 gst_iterator_resync (iter);
2671 case GST_ITERATOR_DONE:
2672 /* all pads iterated, return collected value */
2675 /* iterator returned _ERROR or premature end with _OK,
2676 * mark an error and exit */
2677 g_value_set_boolean (&ret, FALSE);
2682 /* return collected value */
2683 return g_value_get_boolean (&ret);
2686 /* is called with STATE_LOCK
2688 * Pads are activated from source pads to sinkpads.
2691 gst_element_pads_activate (GstElement * element, gboolean active)
2696 GST_CAT_DEBUG_OBJECT (GST_CAT_ELEMENT_PADS, element,
2697 "pads_activate with active %d", active);
2699 iter = gst_element_iterate_src_pads (element);
2701 iterator_activate_fold_with_resync (iter,
2702 (GstIteratorFoldFunction) activate_pads, &active);
2703 gst_iterator_free (iter);
2704 if (G_UNLIKELY (!res))
2707 iter = gst_element_iterate_sink_pads (element);
2709 iterator_activate_fold_with_resync (iter,
2710 (GstIteratorFoldFunction) activate_pads, &active);
2711 gst_iterator_free (iter);
2712 if (G_UNLIKELY (!res))
2716 /* clear the caps on all pads, this should never fail */
2717 iter = gst_element_iterate_pads (element);
2719 iterator_activate_fold_with_resync (iter,
2720 (GstIteratorFoldFunction) clear_caps, &active);
2721 gst_iterator_free (iter);
2722 if (G_UNLIKELY (!res))
2726 GST_CAT_DEBUG_OBJECT (GST_CAT_ELEMENT_PADS, element,
2727 "pads_activate successful");
2734 GST_CAT_DEBUG_OBJECT (GST_CAT_ELEMENT_PADS, element,
2735 "source pads_activate failed");
2740 GST_CAT_DEBUG_OBJECT (GST_CAT_ELEMENT_PADS, element,
2741 "sink pads_activate failed");
2746 GST_CAT_DEBUG_OBJECT (GST_CAT_ELEMENT_PADS, element,
2747 "failed to clear caps on pads");
2752 /* is called with STATE_LOCK */
2753 static GstStateChangeReturn
2754 gst_element_change_state_func (GstElement * element, GstStateChange transition)
2756 GstState state, next;
2757 GstStateChangeReturn result = GST_STATE_CHANGE_SUCCESS;
2760 g_return_val_if_fail (GST_IS_ELEMENT (element), GST_STATE_CHANGE_FAILURE);
2762 state = (GstState) GST_STATE_TRANSITION_CURRENT (transition);
2763 next = GST_STATE_TRANSITION_NEXT (transition);
2765 /* if the element already is in the given state, we just return success */
2766 if (next == GST_STATE_VOID_PENDING || state == next)
2769 GST_CAT_LOG_OBJECT (GST_CAT_STATES, element,
2770 "default handler tries setting state from %s to %s (%04x)",
2771 gst_element_state_get_name (state),
2772 gst_element_state_get_name (next), transition);
2774 switch (transition) {
2775 case GST_STATE_CHANGE_NULL_TO_READY:
2777 case GST_STATE_CHANGE_READY_TO_PAUSED:
2778 if (!gst_element_pads_activate (element, TRUE)) {
2779 result = GST_STATE_CHANGE_FAILURE;
2782 case GST_STATE_CHANGE_PAUSED_TO_PLAYING:
2784 case GST_STATE_CHANGE_PLAYING_TO_PAUSED:
2786 case GST_STATE_CHANGE_PAUSED_TO_READY:
2787 case GST_STATE_CHANGE_READY_TO_NULL:
2788 /* deactivate pads in both cases, since they are activated on
2789 ready->paused but the element might not have made it to paused */
2790 if (!gst_element_pads_activate (element, FALSE)) {
2791 result = GST_STATE_CHANGE_FAILURE;
2793 gst_element_set_base_time (element, 0);
2796 /* In null state release the reference to the clock */
2797 GST_OBJECT_LOCK (element);
2798 clock_p = &element->clock;
2799 gst_object_replace ((GstObject **) clock_p, NULL);
2800 GST_OBJECT_UNLOCK (element);
2803 /* this will catch real but unhandled state changes;
2804 * can only be caused by:
2805 * - a new state was added
2806 * - somehow the element was asked to jump across an intermediate state
2808 g_warning ("Unhandled state change from %s to %s",
2809 gst_element_state_get_name (state),
2810 gst_element_state_get_name (next));
2817 GST_OBJECT_LOCK (element);
2818 result = GST_STATE_RETURN (element);
2819 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
2820 "element is already in the %s state",
2821 gst_element_state_get_name (state));
2822 GST_OBJECT_UNLOCK (element);
2829 * gst_element_get_factory:
2830 * @element: a #GstElement to request the element factory of.
2832 * Retrieves the factory that was used to create this element.
2834 * Returns: the #GstElementFactory used for creating this element.
2835 * no refcounting is needed.
2838 gst_element_get_factory (GstElement * element)
2840 g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
2842 return GST_ELEMENT_GET_CLASS (element)->elementfactory;
2846 gst_element_dispose (GObject * object)
2848 GstElement *element = GST_ELEMENT (object);
2852 GST_CAT_INFO_OBJECT (GST_CAT_REFCOUNTING, element, "dispose");
2854 if (GST_STATE (element) != GST_STATE_NULL)
2857 GST_CAT_DEBUG_OBJECT (GST_CAT_ELEMENT_PADS, element,
2858 "removing %d pads", g_list_length (element->pads));
2859 /* first we break all our links with the outside */
2860 while (element->pads && element->pads->data) {
2861 /* don't call _remove_pad with NULL */
2862 gst_element_remove_pad (element, GST_PAD_CAST (element->pads->data));
2864 if (G_UNLIKELY (element->pads != 0)) {
2865 g_critical ("could not remove pads from element %s",
2866 GST_STR_NULL (GST_OBJECT_NAME (object)));
2869 GST_OBJECT_LOCK (element);
2870 clock_p = &element->clock;
2871 bus_p = &element->bus;
2872 gst_object_replace ((GstObject **) clock_p, NULL);
2873 gst_object_replace ((GstObject **) bus_p, NULL);
2874 GST_OBJECT_UNLOCK (element);
2876 GST_CAT_INFO_OBJECT (GST_CAT_REFCOUNTING, element, "parent class dispose");
2878 G_OBJECT_CLASS (parent_class)->dispose (object);
2886 ("\nTrying to dispose element %s, but it is not in the NULL state.\n"
2887 "You need to explicitly set elements to the NULL state before\n"
2888 "dropping the final reference, to allow them to clean up.\n",
2889 GST_OBJECT_NAME (element));
2895 gst_element_finalize (GObject * object)
2897 GstElement *element = GST_ELEMENT (object);
2899 GST_CAT_INFO_OBJECT (GST_CAT_REFCOUNTING, element, "finalize");
2901 GST_STATE_LOCK (element);
2902 if (element->state_cond)
2903 g_cond_free (element->state_cond);
2904 element->state_cond = NULL;
2905 GST_STATE_UNLOCK (element);
2906 g_static_rec_mutex_free (element->state_lock);
2907 g_free (element->state_lock);
2908 element->state_lock = NULL;
2910 GST_CAT_INFO_OBJECT (GST_CAT_REFCOUNTING, element, "finalize parent");
2912 G_OBJECT_CLASS (parent_class)->finalize (object);
2915 #ifndef GST_DISABLE_LOADSAVE
2917 * gst_element_save_thyself:
2918 * @element: a #GstElement to save.
2919 * @parent: the xml parent node.
2921 * Saves the element as part of the given XML structure.
2923 * Returns: the new #xmlNodePtr.
2926 gst_element_save_thyself (GstObject * object, xmlNodePtr parent)
2929 GstElementClass *oclass;
2930 GParamSpec **specs, *spec;
2933 GValue value = { 0, };
2934 GstElement *element;
2936 g_return_val_if_fail (GST_IS_ELEMENT (object), parent);
2938 element = GST_ELEMENT (object);
2940 oclass = GST_ELEMENT_GET_CLASS (element);
2942 xmlNewChild (parent, NULL, (xmlChar *) "name",
2943 (xmlChar *) GST_ELEMENT_NAME (element));
2945 if (oclass->elementfactory != NULL) {
2946 GstElementFactory *factory = (GstElementFactory *) oclass->elementfactory;
2948 xmlNewChild (parent, NULL, (xmlChar *) "type",
2949 (xmlChar *) GST_PLUGIN_FEATURE (factory)->name);
2953 specs = g_object_class_list_properties (G_OBJECT_GET_CLASS (object), &nspecs);
2955 for (i = 0; i < nspecs; i++) {
2957 if (spec->flags & G_PARAM_READABLE) {
2961 g_value_init (&value, G_PARAM_SPEC_VALUE_TYPE (spec));
2963 g_object_get_property (G_OBJECT (element), spec->name, &value);
2964 param = xmlNewChild (parent, NULL, (xmlChar *) "param", NULL);
2965 xmlNewChild (param, NULL, (xmlChar *) "name", (xmlChar *) spec->name);
2967 if (G_IS_PARAM_SPEC_STRING (spec))
2968 contents = g_value_dup_string (&value);
2969 else if (G_IS_PARAM_SPEC_ENUM (spec))
2970 contents = g_strdup_printf ("%d", g_value_get_enum (&value));
2971 else if (G_IS_PARAM_SPEC_INT64 (spec))
2972 contents = g_strdup_printf ("%" G_GINT64_FORMAT,
2973 g_value_get_int64 (&value));
2974 else if (GST_VALUE_HOLDS_STRUCTURE (&value)) {
2975 if (g_value_get_boxed (&value) != NULL) {
2976 contents = g_strdup_value_contents (&value);
2978 contents = g_strdup ("NULL");
2981 contents = g_strdup_value_contents (&value);
2983 xmlNewChild (param, NULL, (xmlChar *) "value", (xmlChar *) contents);
2986 g_value_unset (&value);
2992 pads = g_list_last (GST_ELEMENT_PADS (element));
2995 GstPad *pad = GST_PAD_CAST (pads->data);
2997 /* figure out if it's a direct pad or a ghostpad */
2998 if (GST_ELEMENT (GST_OBJECT_PARENT (pad)) == element) {
2999 xmlNodePtr padtag = xmlNewChild (parent, NULL, (xmlChar *) "pad", NULL);
3001 gst_object_save_thyself (GST_OBJECT_CAST (pad), padtag);
3003 pads = g_list_previous (pads);
3010 gst_element_restore_thyself (GstObject * object, xmlNodePtr self)
3012 xmlNodePtr children;
3013 GstElement *element;
3015 gchar *value = NULL;
3017 element = GST_ELEMENT (object);
3018 g_return_if_fail (element != NULL);
3021 children = self->xmlChildrenNode;
3023 if (!strcmp ((char *) children->name, "param")) {
3024 xmlNodePtr child = children->xmlChildrenNode;
3027 if (!strcmp ((char *) child->name, "name")) {
3028 name = (gchar *) xmlNodeGetContent (child);
3029 } else if (!strcmp ((char *) child->name, "value")) {
3030 value = (gchar *) xmlNodeGetContent (child);
3032 child = child->next;
3034 /* FIXME: can this just be g_object_set ? */
3035 gst_util_set_object_arg (G_OBJECT (element), name, value);
3036 /* g_object_set (G_OBJECT (element), name, value, NULL); */
3040 children = children->next;
3044 children = self->xmlChildrenNode;
3046 if (!strcmp ((char *) children->name, "pad")) {
3047 gst_pad_load_and_link (children, GST_OBJECT_CAST (element));
3049 children = children->next;
3052 if (GST_OBJECT_CLASS (parent_class)->restore_thyself)
3053 (GST_OBJECT_CLASS (parent_class)->restore_thyself) (object, self);
3055 #endif /* GST_DISABLE_LOADSAVE */
3058 gst_element_set_bus_func (GstElement * element, GstBus * bus)
3062 g_return_if_fail (GST_IS_ELEMENT (element));
3064 GST_CAT_DEBUG_OBJECT (GST_CAT_PARENTAGE, element, "setting bus to %p", bus);
3066 GST_OBJECT_LOCK (element);
3067 bus_p = &GST_ELEMENT_BUS (element);
3068 gst_object_replace ((GstObject **) bus_p, GST_OBJECT_CAST (bus));
3069 GST_OBJECT_UNLOCK (element);
3073 * gst_element_set_bus:
3074 * @element: a #GstElement to set the bus of.
3075 * @bus: the #GstBus to set.
3077 * Sets the bus of the element. Increases the refcount on the bus.
3078 * For internal use only, unless you're testing elements.
3083 gst_element_set_bus (GstElement * element, GstBus * bus)
3085 GstElementClass *oclass;
3087 g_return_if_fail (GST_IS_ELEMENT (element));
3089 oclass = GST_ELEMENT_GET_CLASS (element);
3091 if (oclass->set_bus)
3092 oclass->set_bus (element, bus);
3096 * gst_element_get_bus:
3097 * @element: a #GstElement to get the bus of.
3099 * Returns the bus of the element. Note that only a #GstPipeline will provide a
3100 * bus for the application.
3102 * Returns: the element's #GstBus. unref after usage.
3107 gst_element_get_bus (GstElement * element)
3109 GstBus *result = NULL;
3111 g_return_val_if_fail (GST_IS_ELEMENT (element), result);
3113 GST_OBJECT_LOCK (element);
3114 if ((result = GST_ELEMENT_BUS (element)))
3115 gst_object_ref (result);
3116 GST_OBJECT_UNLOCK (element);
3118 GST_CAT_DEBUG_OBJECT (GST_CAT_BUS, element, "got bus %" GST_PTR_FORMAT,